The present invention relates in general to an apparatus and method for retrofitting storage rack assemblies with push-back systems. More specifically, the present invention comprises a set of rails, supported by a frame structure that not only serves to incline the rails but also keeps the rails at a predetermined distance from each other so that a push-back cart may translate along the rails. The configuration of the rails and frame allows them to be assembled or dropped into place on an existing rack assembly without requiring structural modification of the rack assembly.
Many companies and individuals find it desirable or necessary to have some form of storage rack assemblies to facilitate high density storage. These racks allow one to organize products for quick access while maximizing the effective use of available space. Presently, there are several different styles of storage racks, including selective rack assemblies and drive-in rack assemblies.
In one form of a selective rack assembly, a sturdy, weight-bearing structure is formed from various vertical, horizontal, and diagonal steel members, which are connected to create several stacked horizontal surfaces or shelves. Items, which are typically on pallets, are then placed on the racks. Since the shelves are capable of supporting a great deal of weight, the pallets of material often are placed on the racks with forklifts.
In a conventional drive-in rack, the pallets (on which the items to be stored are placed) directly provide much of the load support, contrary to what occurs with the selective racks. In the selective racks, the loaded pallets are slid onto horizontal support members, which pass underneath and support each pallet along multiple directions. On the other hand, in a conventional drive-in rack, the pallets are typically supported by the storage rack assembly along only two parallel sides of each pallet. Since conventional drive-in racks only have two parallel, horizontal weight-bearing support rails per lane, a forklift operator may drive into a lane between parallel support members to remove a pallet.
A drawback of the conventional drive-in rack is that, before the second load of an upper level may be accessed, all of the loads in front of the desired load that are at or below the level on which the desired load rests must first be removed. Thus, unless considerable rehandling is acceptable, a drive-in bay provides effective storage for just one type of item. Further, the forklift time required to place loads in and remove loads from drive-in racks is considerable, since the support rails are so close together that the forklift operator must move very slowly to preclude hitting the racks and damaging the racks or the merchandise.
The idea of retrofitting push-back lanes in drive-in racks has been used in the prior art. However, the prior art retrofitting systems require substantial modification of the existing rack assembly. In the prior art, the existing drive-in rails and supports are removed and replaced with new load beams so that a conventional push-back system may be installed.
It is an overall object of the present invention to provide push-back systems that may be rapidly and inexpensively retrofitted into existing storage racks with minimal modification of the existing storage racks. Push-back systems provide greater selectivity and increase the speed of put-away and retrieval operations. Using a push-back system, each lane of a storage rack may contain a unique item, and yet each item may be easily accessed without rehandling items in other lanes to get to the desired item.
It is another object of the present invention to provide a self-contained push-back module, which may be assembled on the ground and then lifted into position with a forklift, resulting in significant installation labor savings.
It is a further object of the present invention to build the rail pitch, which results in gravitational force acting on the push-back cart, into the push-back modules instead of the load beams. This allows the current invention to be attached to almost any existing storage rack.
It is yet another object of the present invention to standardize the push-back modules so that little custom engineering is required, and the modules can be sold as a catalog item. Unlike the invention disclosed herein, prior art systems require extensive custom engineering for each retrofit.